GB2211789A

GB2211789A - Driving arrangements for selective printers

Info

Publication number: GB2211789A
Application number: GB8818972A
Authority: GB
Inventors: Thomas Schaf; Armin Weise; Hans Gropp
Original assignee: TA Triumph Adler AG
Current assignee: TA Triumph Adler AG
Priority date: 1987-10-31
Filing date: 1988-08-10
Publication date: 1989-07-12
Also published as: JPH01154785A; FR2622510A1; IT8821150A0; GB8818972D0; SE8802427D0; SE8802427L; CH680425A5; IT1217958B

Description

0 n n 4,e- 117 8 9 - 1 Imprinting Machines This invention relates to

imprinting machines, such as typewriters.

It has long been the aim of typewriter designers to reduce as far as possible the masses which have to be displaced in operation. This applies in particular to those typewriters in which the type carrier, for example a type wheel, is disposed on a carriage movable along the platen. Usually, the type wheel is adjusted by means of a motor and the impression is effected by an electro-magnet.

Proposals have already been made for providing a motor-driven cam for the impression function. Proposals of this kind can be seen from DEAS 18 07 387, DE-OS 21 01 995 and DEPS 27 17 975. In is the last two printed documents mentioned, it can be seen in particular that the total mass of the carriage can be kept comparatively low as a result of the fact that the motor for the drive of the cam is situated in the machine frame. Since its rotary motion has to be transmitted to the carriage, however, fairly considerable additional expense is necessary for this purpose. In addition, either a control magnet or a synchronizing device is needed for these two known devices, so that the total expense of such a typewriter is comparatively high.

It is the object of the invention to be able to effect a further reduction in mass in a typewriter of the type in question, with simple mechanical con- struction.

According to the invention there is provided an imprinting machine, such as a typewriter, having a -multi-type carrier and a rotary motor which is oper ated intermittently to impress individual characters, wherein the said motor also powers a separate function of the machine through a rotary cam and a rocking lever.

As a result of the fact that the motor for the impression of selected characters can also be used for the drive of further functions, further actuating devices, such as a motor or an electro-magnet for example, are saved. Apart from the reduction in the masses to be moved, considerable savings in costs can be achieved. In addition, the space on the printing mechanism carriage freed by the drive saved can be used otherwise, for example by a larger ribbon cassette.

One form of typewriter in accordance with the invention will now be described, by way of example, with reference to the accompanying drawing, which is a side view of a printing-mechanism carriage of a typewriter, although the drive motor for the type wheel is not included in the illustration for reasons of graphic clarity.

Disposed on the printing-mechanism carriage 1 is a pedestal 2 on which a rotary motor 3 is mounted. Secured to the drive shaft 4 of the motor is a cam 5 which can drive a hammer 6 so that a set character 7 of the type wheel 8 is moved towards the -platen 9 for impression. In its position of rest, the hammer 6 bears against a stop 11 under the action of a spring 10.

Also secured to the motor shaft 4 is another rotary cam, in the form of an eccentric 12. Bearing against this is the roller 13 of a pivoted rocking lever 14, the pivot pin 15 of which is fitted to the pedestal 2. A spring 16 urges the roller 13 into contact with the eccentric 12. At its upper end, the lever 14 is provided with a pawl 17 cooperating with a ratchet wheel 18 which is mounted for rotation on a part 19 of the carriage 1. This ratchet wheel comprises a coupling member 20 which projects into a ribbon cassette, for example, when one is operatively positioned on the carriage.

In operation, the motor 3 is intermittently operated, completing one revolution in each operative is cycle. When the shaft 4 rotates, the hammer 6 is moved towards the platen 9 by the action of the cam 5.

The arrangement is preferably such that the hammer covers the last part of its movement in free flight, i.e. it is t hrown towards the platen and loses contact with the cam.

The eccentric 12 is also turned at the same time as the cam, to pivot the lever 14 against the action of the spring 16 so that the ratchet wheel 18 is turned by one step. This rotary movement is trans mitted by the coupling member 20 to the ribbon.

Thus it can be seen that a plurality of functions, in the present example actuation of the printing hammer and the ribbon, can be driven by means of one and the same motor. By appropriate formation of the cam 5 and/or of the eccentric 12, it is also easily possible to stagger the different movements in time so that they are not superimposed. As a result, a weaker and hence cheaper motor can be used, resulting in a further possible reduction in costs.

By means of different current-application - 4 patterns for the motor 3, different impression strengths for the printing hammer can also be produced. This should not, however, have any effect on the ribbon drive. Also the drive of the second function may likewise be derived from the cam 5 instead of from the eccentric 12. Furthermore, by reversing the direction of rotation of the motor shaft 4, it is possible to derive motion functions without a superimposition of movements taking place. Partial rotations of cam 5 and/or eccentric 12 are also conceivable.

In other possible modifications of the invention, the auxiliary drive obtained from the motor may be employed to effect raising and lowering of the printing ribbon to the imprinting level or of a correction ribbon, optionally through the cam.5 for the impression hammer.

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Claims

CLAIMS:

1. An imprinting machine, such as a typewriter, having a multiple-type carrier and a rotary motor which is operated intermittently to impress individual characters, wherein the said motor also powers a separate function of the machine through a rotary cam and a rocking lever.

2. A machine according to claim 1, wherein the said eccentric and rocking lever are arranged to actuate a printing ribbon feed.

3. An imprinting machine substantially as herein described with reference to the accompanying drawing. 15 Published 1989 at The Patent Office, State House, 66.171 High Holborn, London WC1R 4TP. Auther copies maybe obtained from The Patent Office.